The attacks did not change the desire of reaching new heights. It just moved the focus from North America to the Arabian Peninsula.
And it is not even a question of funds as the Kingdom Tower - www.kingdtomtowerskyscraper.com - will cost only 1.2 billion dollars according to this site.
And as Adrian Smith - the architect - has put it in an interview, the cost of the building would not be sustainable if the owners wouldn't own lots of land near the building site. Tell me a place in the USA where a person owns thousands of acres of land in a big city ...
But this is another discussion, and I wholeheartedly agree with the author about balancing about openness and security - it is something that I did not feel right back when I was in the US.

People are always asking me to name my favorite Chicago building and I demur, saying it’s like being asked to name a favorite child. But here’s a question I’ll entertain: Which Chicago building best reveals how the September 11 terrorist attacks either did or did not change architecture? That’...